An interventional study of Aspirin in Platelet Aggregation, sponsored by Vanderbilt University. Withdrawn at 1 site in United States. Open to male participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2015-12-07.
Sponsored by Vanderbilt University · Not applicable, Interventional, and Basic science
Aspirin has been shown to reduce cardiovascular events in at risk individuals. Elucidation of mechanisms of aspirin resistance and a possible loss of effect of aspirin over time with chronic aspirin treatment necessitate a more precise method of measuring the "release phase" of platelet activation, including the release of dense granules from platelets.
This is a proposal for a pilot study to evaluate the feasibility of measuring 5-hydroxytryptamine (5-HT) release from platelets as an indicator of dense granule release during platelet activation in volunteers taking aspirin.
One phase of platelet response to activating agonists involves release of dense granules, which are known to contain 5HT (serotonin) and ATP. There are various methods of measuring the degranulation of platelets: ATP release can be measured using a lumiaggregometer, and release of 14C radiolabeled 5-HT from platelets. Using the aggregometer and a 14C labeled 5-HT assay can be used to measure 5-HT release from platelets.
Our experience suggests that ADP-induced ATP release is insensitive to detect very low levels of platelet dense granule release, which occurs in aspirin-treated subjects. The pilot study will permit optimizing the method for reliably detecting low levels of 5HT release in patients who achieve submaximal inhibition of the cyclooxygenase during aspirin treatment.
Vanderbilt University is the lead sponsor of 508 studies on the registry; 19 are open to participants now.
Of its 7 completed or terminated interventional studies of FDA-regulated products, 5 (71%) have results posted.
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Exclusion Criteria:
Female subjects will be excluded to avoid possible confounding uterine smooth muscle production of prostaglandins which various throughout the menstrual cycle.
40 mg non-enteric coated ASA once daily for 21 + or - 2 days
Drug: Aspirin
40 mg non-enteric coated ASA once daily for 21 + or - 2 days
The primary measurement will be platelet 5-HT release induced by ADP after 1 and 2 weeks administration of daily ASA.
Time frame: 3 weeks
Measurements will include platelet COX-1 activity, flow cytometric measurement of markers of platelet activation, platelet aggregation and ATP release, and serum thromboxane B2 (TxB2) levels, at each timepoint.
Time frame: 3 weeks
This study is withdrawn, as verified in Dec 2015. You cannot join it, but the record below documents what was studied.
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Vanderbilt University